Hello Friends,

The basic question is what is a Linux kernel?
Now the kernel is an important part of the Linux operating system. The kernel manages the resources of Linux such as:

• File management
• Multitasking
• Memory management
• I/O management
• Process management
• Device management
• Networking support including IPv4 and IPv6
• Advanced features such as virtual memory, shared libraries, demand loading, shared copy-on-write executables etc

The job of the kernel is to decide who will use these resources and for how long and when. It runs your programs or sets up to execute binary files.

The kernel acts as an intermediary between the computer hardware and various applications or computer software.

Hello Friends,

Routers are very essential element in networked office systems. Routers are similar to hubs. Routers allow connections of shared communication between different computer. The Computers attached to the shared routers can access the same printers, files, or an internet connection.

Hello Friends,

 Following are the commands to open tcp or udp ports on the server.

Before using commands for opening the port please make sure the specific port is already opend and what is the use of that port.

you can verify the port with

netstat -nap | grep : <port no>

1.you can open TCp port with

iptables -A INPUT  -p tcp –dport <port no> -j ACCEPT

2. You can open UDP port with

iptables -A INPUT -p udp –sport <port no>  -j ACCEPT 

 after that

3 service iptables save

and for flushhing iptables us

iptables -F 

Hello Friends,

Following are the commands to open tcp or udp ports on the server.

Before using commands for opening the port please make sure the specific port is already opend and what is the use of that port.

you can verify the port with

netstat -nap | grep :

1.you can open TCp port with

iptables -A INPUT -p tcp –dport
-j ACCEPT

2. You can open UDP port with

iptables -A INPUT -p udp –sport
-j ACCEPT

after that

3 service iptables save

and for flushhing iptables us

iptables -F

WAN -Wide-area networks is a communication network that is carried out in a wide areas that are regional, nationwide, or worldwide in geographic area. In this type of communication network, devices such as telephone lines, satellite dishes, or radio waves are used.

A WAN administrator manages the wide area communications network. He configures, monitors & implements of all networking hardware such as modems, DSU/CSUs, routers and switches. WAn accelerator is used to speeds up transmission in a wide area network. Wan router is used to
WAN monitoring plays an important role in providing critical visibility into how the WAN, application & remote uses are operating. WAN monitoring is necessary to improve service. WAN monitoring can help location where a problem originates, isolate the cause & source of the problem & provide performance information.

As you may noticed, using Ping to comprehensively diagnose the location of an outage or slowdown can be rather redious. Fortunately, there is a tool that can ease some of that tedium. Traceroute (or Tracert, as the tool is named under Windows). You initiate a traceroute by running the program and passing it the name of the destination host. Every TCP/IP connection between yourself & that host is tested to ascertain both network connectivity & response time. The Traceroute uitility send a special traceroute package to the firts upstream host (normally your TCP/IP gateway), listing the destination of the traceroute. That forst upstream host, if alive, responds to the originator by sending the equivalent of a ping response, with a confirmation of receipt, and forwards the traceroute packet on the next upstream host. This process continues until the destination is reached or the TTL for yje tracetoute packet is exceeded.

Like Ping, The Traceroute utility has a number of cinfiguration options. Traceroute is extremely useful for isolating the point of the network failure, because it can shoe which gateway device is not responding and even reveal whether one port on a gateway device is dead. Traceroute can also show you, with the response time statistic for each response, where network slowdowns are taking place. When used in combination, Traceroute & Ping are, perhaps, the most valuable software tools available to the adminstartor of the TCP/IP network.